ld: adjust PE base relocations testcase

mcore-pe and sh-pe pointed out that the testcase added by 6fa7408d72
("ld: don't generate base relocations in PE output for absolute
symbols") wasn't quite generic enough yet. Copy entry point stuff from
another test and increase alignment to also cover targets with a page
size lower than 4k.

Despite all of this the test needs to be xfail-ed for mcore, as this
target isn't included in the set getting DLL_SUPPORT enabled in
emultempl/pe.em, and hence no base relocations get generated there
(yet).

ld/ChangeLog

@@ -1,3 +1,9 @@
+2021-03-09  Jan Beulich  <jbeulich@suse.com>
+
+	* testsuite/ld-pe/reloc.s: Add entry point symbols. Increase
+	alignment to 4k.
+	* testsuite/ld-pe/reloc.d: xfail for mcore.
+
 2021-03-09  Jan Beulich  <jbeulich@suse.com>
 
 	* testsuite/ld-scripts/alignof.exp,

ld/testsuite/ld-pe/reloc.d

@@ -1,6 +1,7 @@
 #name: PE base relocations
 #ld: --enable-reloc-section
 #objdump: -p
+#xfail: mcore-*-*
 
 .*:     file format .*
 

ld/testsuite/ld-pe/reloc.s

@@ -1,5 +1,12 @@
+	.text
+	.global _start
+	.global _mainCRTStartup
+_start:
+_mainCRTStartup:
+	.byte 1
+
 	.data
-	.p2align 4
+	.p2align 12
 start:
 	.dc.a	__image_base__
 	.dc.a	start