x87: missing memory write for 32bit floats for fst

Subject: https://github.com/rfalke/decompiler-subjects/blob/master/from_holdec/i386_x87_fpu/ia32_elf/subject.exe
Output:
```
int32_t FST(void) {
// 0x804b100
g2 = 0x40490fdb;
char v1 = *(char *)&g3; // 0x804b11b
printf("FST(pi as float) should=0xdb 0x0f 0x49 0x40 is=0x%02x 0x%02x 0x%02x 0x%02x\n", 219, (int32_t)v1, (int32_t)g4, (int32_t)g5);
*(float64_t *)&g2 = 3.1415926535897931;
char v2 = *(char *)&g7; // 0x804b153
char v3 = *(char *)&g3; // 0x804b173
printf("FST(pi as double) should=0x18 0x2d 0x44 0x54 0xfb 0x21 0x09 0x40 is=0x%02x 0x%02x 0x%02x 0x%02x 0x%02x 0x%02x 0x%02x 0x%02x\n", 24, (int32_t)v3, (int32_t)g4, (int32_t)g5, (int32_t)g6, (int32_t)v2, (int32_t)g8, (int32_t)g9);
*(float80_t *)&g2 = 3.141592653589793116L;
unsigned char v4 = *(char *)&g7; // 0x804b1bb
unsigned char v5 = *(char *)&g3; // 0x804b1db
printf("FST(pi as long double) should=0x35 0xc2 0x68 0x21 0xa2 0xda 0x0f 0xc9 0x00 0x40 is=0x%02x 0x%02x 0x%02x 0x%02x 0x%02x 0x%02x 0x%02x 0x%02x 0x%02x 0x%02x\n", 0, (int32_t)v5, (int32_t)g4, (int32_t)g5, (int32_t)g6, (int32_t)v4, (int32_t)g8, (int32_t)g9, (int32_t)g10, (int32_t)g11);
return 0;
}
```
For the 64bit and 80bit there is a write (`*(float64_t *)&g2 = 3.1415926535897931`,...) visible in the output but not for the first 32bit fst.

Start with the linked decompiler subject executable and the generated FST output, focusing on the 32-bit float store before the existing 64-bit and 80-bit cases. Compare the emitted memory writes and expected byte sequences; done means the 32-bit fst produces a visible write matching the expected float bytes.

Written by the indexing model from the issue text.