ld: Add a test for PR ld/27259

PR ld/27259
	* testsuite/ld-elf/pr27259.d: New file.
	* testsuite/ld-elf/pr27259.s: Likewise.

ld/ChangeLog

@@ -1,3 +1,9 @@
+2021-01-28  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR ld/27259
+	* testsuite/ld-elf/pr27259.d: New file.
+	* testsuite/ld-elf/pr27259.s: Likewise.
+
 2021-01-28  Alan Modra  <amodra@gmail.com>
 
 	PR 27259

ld/testsuite/ld-elf/pr27259.d

@@ -0,0 +1,7 @@
+#ld: --gc-sections -e _start
+#target: [check_gc_sections_available]
+#readelf: -SW
+
+#...
+ +\[ *[0-9]+\] \.stack_sizes +PROGBITS +0+ +[0-9a-f]+ 0+1 +00 +L +[0-9] .*
+#pass

ld/testsuite/ld-elf/pr27259.s

@@ -0,0 +1,14 @@
+	.section .stack_sizes,"o",%progbits,live,unique,0
+live:
+	.byte 1
+
+	.section .stack_sizes,"o",%progbits,dead,unique,1
+dead:
+	.byte 2
+
+	.section .text.main,"ax",%progbits
+	.globl _start
+_start:
+	.byte 0
+	.section .note,"",%note
+	.dc.a live