Don't quote -target cmdline opt to TARGET_SWIFTFLAGS

The double quote marks are preserved in this makefile setting, so
the -target <triple> command line option & value are passed as a
single word, which is not recognized by swiftc, when running the
testsuite against environments where we need to specify the target
value.  Not normally used when running the testsuite on a native
system.

Author: jasonmolenda

lldb/packages/Python/lldbsuite/test/builders/darwin.py

@@ -122,7 +122,7 @@ def getSwiftTargetFlags(self, arch):
         if vendor is None or os is None or version is None or env is None:
             return []
         return [
-            'TARGET_SWIFTFLAGS="-target {}-{}-{}{}{}"'.format(
+            'TARGET_SWIFTFLAGS=-target {}-{}-{}{}{}'.format(
                 arch, vendor, os, version, (("-" + env) if env else ""))
         ]