[FFI/JTreg]Remove the pragma lines for AIX in test suites

The intention of the changes is to avoid conflicts
with our own code with 4-byte alignment for double on
AIX which already supports both the default setting
by the compiler and the natural alignment for double.

Fixes: #eclipse-openj9/openj9/issues/18940,
#eclipse-openj9/openj9/issues/18941,
#eclipse-openj9/openj9/issues/18942, 
#eclipse-openj9/openj9/issues/18943

Signed-off-by: ChengJin01 <jincheng@ca.ibm.com>

test/jdk/java/foreign/nested/libNested.c

@@ -26,9 +26,6 @@
 #else
 #define EXPORT
 #endif
-#ifdef _AIX
-#pragma align (natural)
-#endif
 
 struct S1{ double f0; long long f1; double f2; int f3; };
 union U1{ short f0; long long f1; short f2; char f3[4][3]; };
@@ -95,7 +92,3 @@ EXPORT struct S13 test_S13(struct S13 arg, struct S13(*cb)(struct S13)) { return
 EXPORT struct S14 test_S14(struct S14 arg, struct S14(*cb)(struct S14)) { return cb(arg); }
 EXPORT union U16 test_U16(union U16 arg, union U16(*cb)(union U16)) { return cb(arg); }
 EXPORT struct S15 test_S15(struct S15 arg, struct S15(*cb)(struct S15)) { return cb(arg); }
-
-#ifdef _AIX
-#pragma align (reset)
-#endif

test/jdk/java/foreign/shared.h

@@ -34,9 +34,6 @@
 #else
 #define EXPORT
 #endif
-#ifdef _AIX
-#pragma align (natural)
-#endif
 
 struct S_I { int p0; };
 struct S_F { float p0; };
@@ -123,7 +120,3 @@ struct S_PPF { void* p0; void* p1; float p2; };
 struct S_PPD { void* p0; void* p1; double p2; };
 struct S_PPP { void* p0; void* p1; void* p2; };
 struct S_FFFF { float p0; float p1; float p2; float p3; };
-
-#ifdef _AIX
-#pragma align (reset)
-#endif