s390: [builtins] Add tests for embedding with .byte directive

Port 7c14a408

Original Commit Message:

    It turns out that .incbin can be problematic for build systems, in
    that the included binary file is not detected as a build-time
    dependency.

    The alternative is .byte inclusion, which we test here.

R=jgruber@chromium.org, joransiu@ca.ibm.com, michael_dawson@ca.ibm.com
BUG=
LOG=N

Change-Id: Ie42da993ae61964eb3f02f328333ec140902d929
Reviewed-on: https://chromium-review.googlesource.com/906688Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Junliang Yan <jyan@ca.ibm.com>
Cr-Commit-Position: refs/heads/master@{#51148}

test/cctest/test-isolate-independent-builtins.cc

@@ -217,8 +217,7 @@ TEST(GenerateTestFunctionData) {
   "0x03, 0x00, 0x00, 0x00, 0x00\n"
 #elif V8_TARGET_ARCH_S390
 #define FUNCTION_BYTES                               \
-  ".byte 0xa7, 0x18, 0x00, 0x03, 0xc0, 0x2f, 0x00, " \
-  "0x00, 0x00, 0x04, 0xb9, 0x04, 0x00, 0x22, 0x1a, 0x21, 0x07, 0xfe\n"
+  ".byte 0xb9, 0x08, 0x00, 0x23, 0x07, 0xfe\n"
 #else
 #error "Unknown architecture."
 #endif