[ELF,test] Add eh-frame-nonzero-offset-riscv.s for #65966

I plan to define RISCV::relocateAllocate in a subsequent change.
Add a test to verify
`else if (auto *ehIn = dyn_cast<EhInputSection>(&sec)) secAddr += ehIn->getParent()->outSecOff;`

Author: MaskRay

lld/test/ELF/eh-frame-nonzero-offset-riscv.s

@@ -0,0 +1,53 @@
+// REQUIRES: riscv
+// RUN: rm -rf %t && split-file %s %t && cd %t
+
+// RUN: llvm-mc -filetype=obj -triple=riscv64 a.s -o a.o
+// RUN: ld.lld a.o -T eh-frame-non-zero-offset.t -o non-zero
+// RUN: llvm-readelf --program-headers --unwind --symbols -x .eh_frame non-zero | FileCheck --check-prefix=NONZERO %s
+// RUN: ld.lld a.o -T eh-frame-zero-offset.t -o zero
+// RUN: llvm-readelf --program-headers --unwind --symbols -x .eh_frame zero | FileCheck --check-prefix=ZERO %s
+
+// NONZERO:      {{[0-9]+}}: 0000000000000088 {{.*}} __eh_frame_start
+// NONZERO-NEXT: {{[0-9]+}}: 00000000000000b4 {{.*}} __eh_frame_end
+
+// NONZERO:      0x00000088 10000000 00000000 017a5200 01780101 .
+// NONZERO-NEXT: 0x00000098 1b0c0200 10000000 18000000 5cffffff .
+// NONZERO-NEXT: 0x000000a8 04000000 00000000 00000000          .
+
+// ZERO:      {{[0-9]+}}: 0000000000000008 {{.*}} __eh_frame_start
+// ZERO-NEXT: {{[0-9]+}}: 0000000000000034 {{.*}} __eh_frame_end
+
+// ZERO:      0x00000008 10000000 00000000 017a5200 01780101 .
+// ZERO-NEXT: 0x00000018 1b0c0200 10000000 18000000 dcffffff .
+// ZERO-NEXT: 0x00000028 04000000 00000000 00000000          .
+
+//--- eh-frame-non-zero-offset.t
+SECTIONS {
+  .text : { *(.text .text.*) }
+  .eh_frame : {
+    /* Padding within .eh_frame */
+    . += 128;
+    __eh_frame_start = .;
+    *(.eh_frame) ;
+    __eh_frame_end = .;
+  }
+}
+
+//--- eh-frame-zero-offset.t
+SECTIONS {
+  .text : { *(.text .text.*) }
+  .eh_frame : {
+    __eh_frame_start = .;
+    *(.eh_frame) ;
+    __eh_frame_end = .;
+  }
+}
+
+//--- a.s
+.section .text.01, "ax",%progbits
+.global f1
+.type f1, %function
+f1:
+.cfi_startproc
+.space 4
+.cfi_endproc