Fixed crash when using self in imp_implementationWithBlock on armv7a

Test/BlockImpTest.m

@@ -26,6 +26,7 @@ int main(void)
 {
 	__block int b = 0;
 	void* blk = ^(id self, int a) {
+		assert([self class] == [Foo class]);
 		b += a; 
 		return b; };
 	blk = Block_copy(blk);
@@ -45,6 +46,7 @@ int main(void)
 	assert(imp_getBlock(imp) != (blk));
 
 	blk = ^(id self) {
+		assert([self class] == [Foo class]);
 		struct big b = {1, 2, 3, 4, 5};
 		return b;
 	};

block_trampolines.S

@@ -126,7 +126,7 @@
 .thumb
 .macro trampoline arg0, arg1
 	sub r12, pc, #4095
-	mov \arg0, \arg1            // Move self over _cmd
+	mov \arg1, \arg0            // Move self over _cmd
 	ldr \arg0, [r12, #-5]       // Load the block pointer over self
 	ldr r12, [r12, #-1]         // Jump to the block function
 	bx  r12
@@ -134,7 +134,7 @@
 #	else
 .macro trampoline arg0, arg1
 	sub r12, pc, #4096
-	mov \arg0, \arg1            // Move self over _cmd
+	mov \arg1, \arg0            // Move self over _cmd
 	ldr \arg0, [r12, #-8]       // Load the block pointer over self
 	ldr pc, [r12, #-4]          // Jump to the block function
 .endm