[test] Check LD_LIBRARY_PATH a little less strictly.

LD_LIBRARY_PATH is one of the few environment variables the LLVM 'lit'
tool /doesn't/ strip out, presumably because on some Linux systems
it's necessary to run some of the built products being tested.
However, the Swift driver also uses LD_LIBRARY_PATH when providing -L
options to the script interpreter on Linux. Weaken some of our tests
when there's an LD_LIBRARY_PATH in the environment.

(There are similar environment variables on OS X, but we don't have to
do anything special there because lit /does/ strip those out. This is
presumably okay because all of LLVM's load-time dependencies on OS X
are in standard system locations.)

https://bugs.swift.org/browse/SR-813

Author: jrose-apple

test/Driver/environment.swift

@@ -1,5 +1,7 @@
 // UNSUPPORTED: objc_interop
 // Apple's "System Integrity Protection" makes this test fail on OS X.
 
-// RUN: %swift_driver -target x86_64-unknown-gnu-linux -L/foo/ -driver-use-frontend-path %S/Inputs/print-var.sh %s LD_LIBRARY_PATH | FileCheck %s
+// RUN: %swift_driver -target x86_64-unknown-gnu-linux -L/foo/ -driver-use-frontend-path %S/Inputs/print-var.sh %s LD_LIBRARY_PATH | FileCheck -check-prefix=CHECK${LD_LIBRARY_PATH+_LAX} %s
+
 // CHECK: {{^/foo/:[^:]+/lib/swift/linux$}}
+// CHECK_LAX: {{^/foo/:[^:]+/lib/swift/linux}}

test/Driver/options-interpreter.swift

@@ -17,8 +17,9 @@
 // RUN: %swift_driver -### -target x86_64-apple-macosx10.9 -resource-dir /RSRC/ %s | FileCheck -check-prefix=CHECK-RESOURCE-DIR-ONLY %s
 // CHECK-RESOURCE-DIR-ONLY: # DYLD_LIBRARY_PATH=/RSRC/macosx{{$}}
 
-// RUN: %swift_driver -### -target x86_64-unknown-linux-gnu -resource-dir /RSRC/ %s | FileCheck -check-prefix=CHECK-RESOURCE-DIR-ONLY-LINUX %s
+// RUN: %swift_driver -### -target x86_64-unknown-linux-gnu -resource-dir /RSRC/ %s | FileCheck -check-prefix=CHECK-RESOURCE-DIR-ONLY-LINUX${LD_LIBRARY_PATH+_LAX} %s
 // CHECK-RESOURCE-DIR-ONLY-LINUX: # LD_LIBRARY_PATH=/RSRC/linux{{$}}
+// CHECK-RESOURCE-DIR-ONLY-LINUX_LAX: # LD_LIBRARY_PATH=/RSRC/linux{{$|:}}
 
 // RUN: %swift_driver -### -target x86_64-apple-macosx10.9 -L/foo/ %s | FileCheck -check-prefix=CHECK-L %s
 // CHECK-L: # DYLD_LIBRARY_PATH={{/foo/:[^:]+/lib/swift/macosx$}}
@@ -57,8 +58,10 @@
 // CHECK-COMPLEX-DAG: DYLD_FRAMEWORK_PATH=/foo/:/bar/:/abc/{{$| }}
 // CHECK-COMPLEX-DAG: DYLD_LIBRARY_PATH={{/foo2/:/bar2/:[^:]+/lib/swift/macosx($| )}}
 
-// RUN: %swift_driver -### -target x86_64-unknown-linux-gnu -L/foo/ %s | FileCheck -check-prefix=CHECK-L-LINUX %s
+// RUN: %swift_driver -### -target x86_64-unknown-linux-gnu -L/foo/ %s | FileCheck -check-prefix=CHECK-L-LINUX${LD_LIBRARY_PATH+_LAX} %s
 // CHECK-L-LINUX: # LD_LIBRARY_PATH={{/foo/:[^:]+/lib/swift/linux$}}
+// CHECK-L-LINUX_LAX: # LD_LIBRARY_PATH={{/foo/:[^:]+/lib/swift/linux($|:)}}
 
-// RUN: env LD_LIBRARY_PATH=/abc/ %swift_driver_plain -### -target x86_64-unknown-linux-gnu -L/foo/ -L/bar/ %s | FileCheck -check-prefix=CHECK-LINUX-COMPLEX %s
+// RUN: env LD_LIBRARY_PATH=/abc/ %swift_driver_plain -### -target x86_64-unknown-linux-gnu -L/foo/ -L/bar/ %s | FileCheck -check-prefix=CHECK-LINUX-COMPLEX${LD_LIBRARY_PATH+_LAX} %s
 // CHECK-LINUX-COMPLEX: # LD_LIBRARY_PATH={{/foo/:/bar/:[^:]+/lib/swift/linux:/abc/$}}
+// CHECK-LINUX-COMPLEX_LAX: # LD_LIBRARY_PATH={{/foo/:/bar/:[^:]+/lib/swift/linux:/abc/($|:)}}