sema: bump num_passing to 102

Tests 5-101 pass without code changes — the struct_init_field_type,
enum field lookup, and union field type infrastructure unlocked all
sema_tests plus lib/ files through neghf2.zig.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

stage0/corpus.zig

@@ -3,7 +3,7 @@
 /// `num_passing` controls how many files are tested and pre-generated.
 /// Both build.zig and stages_test.zig import this file.
 /// To enable more tests: just increment `num_passing`.
-pub const num_passing: usize = 5;
+pub const num_passing: usize = 102;
 
 pub const files = [_][]const u8{
     "stage0/sema_tests/empty.zig",
@@ -103,6 +103,8 @@ pub const files = [_][]const u8{
     "stage0/sema_tests/cross_fn_memoized_call.zig",
     "stage0/sema_tests/nested_inline_dead_blocks.zig",
     "stage0/sema_tests/comptime_arg_dbg.zig",
+    "stage0/sema_tests/xor_const.zig",
+    "stage0/sema_tests/export_fn_bitcast.zig",
     "lib/std/crypto/codecs.zig",
     "lib/std/os/uefi/tables/table_header.zig",
     "lib/std/zig/llvm.zig",

stage0/sema_tests/export_fn_bitcast.zig

@@ -0,0 +1,3 @@
+export fn neg(a: f16) f16 {
+    return @bitCast(@as(u16, @bitCast(a)) ^ @as(u16, 0x8000));
+}

stage0/sema_tests/xor_const.zig

@@ -0,0 +1,3 @@
+export fn xor_const(a: u16) u16 {
+    return a ^ 0x8000;
+}