Remove returns from main

tests/passing/peggy_comparison/branch_hoisting.bril

@@ -1,5 +1,5 @@
 # ARGS: 0
-@main(n: int): int {
+@main(n: int) {
     zero: int = const 0;
     x: int = id zero;
     y: int = id zero;
@@ -29,5 +29,5 @@
     jmp .pred;
 
 .end:
-    ret x;
+    print x;
 }

tests/passing/peggy_comparison/conditional_constant_folding.bril

@@ -1,5 +1,5 @@
 # ARGS: 4
-@main(x: int): int {
+@main(x: int) {
     five: int = const 5;
     four: int = const 4;
     twenty: int = const 20;
@@ -25,5 +25,4 @@
 
 .end:
     print res;
-    ret res;
 }

tests/passing/peggy_comparison/dead_loop_deletion.bril

@@ -1,4 +1,4 @@
-@main(): int {
+@main {
     j: int = const 3;
     i: int = const 0;
     forty: int = const 40;
@@ -16,5 +16,5 @@
 .loop_end:
     j: int = const 2;
 
-    ret j;
+    print j;
 }

tests/passing/peggy_comparison/if_true.bril

@@ -1,12 +1,13 @@
-@main(x: int): int {
+# ARGS: 20
+@main(x: int) {
     cond: bool = const true;
     br cond .thn .els;
 
 .thn:
-    ret x;
+    print x;
 
 .els:
     one: int = const 1;
     res: int = sub x one;
-    ret res;
+    print res;
 }

tests/passing/peggy_comparison/loop_based_code_motion.bril

@@ -1,4 +1,4 @@
-@main: int {
+@main {
     x: int = const 0;
     three: int = const 3;
 
@@ -15,5 +15,5 @@
     five: int = const 5;
     x: int = mul x five;
 
-    ret x;
+    print x;
 }

tests/passing/peggy_comparison/loop_invariant_code_motion.bril

@@ -1,3 +1,4 @@
+# ARGS: 30 10
 @main(n: int, m: int) {
     i: int = const 0;
     twenty: int = const 20;

tests/passing/peggy_comparison/loop_peeling.bril

@@ -1,4 +1,5 @@
-@main(n: int): int {
+# ARGS: 5
+@main(n: int) {
     x: int = const 0;
     i: int = const 0;
 
@@ -14,5 +15,5 @@
     jmp .loop_test;
 
 .loop_end:
-    ret x;
+    print x;
 }

tests/passing/peggy_comparison/loop_unroll.bril

@@ -1,4 +1,4 @@
-@main: int {
+@main {
     i: int = const 0;
     one: int = const 1;
 
@@ -11,5 +11,5 @@
     jmp .loop_test;
 
 .loop_end:
-    ret i;
+    print i;
 }

tests/passing/peggy_comparison/simple_loop_unswitch.bril

@@ -1,5 +1,5 @@
 # ARGS: 40
-@main(n: int): int {
+@main(n: int) {
     one: int = const 1;
     zero: int = const 0;
     i: int = id zero;
@@ -24,5 +24,5 @@
     jmp .loop_test;
 
 .loop_end:
-    ret j;
+    print j;
 }