[Issue 21720] New: Struct with destructor cannot be emplaced in betterC

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=21720

          Issue ID: 21720
           Summary: Struct with destructor cannot be emplaced in betterC
           Product: D
           Version: D2
          Hardware: x86_64
                OS: Linux
            Status: NEW
          Severity: regression
          Priority: P1
         Component: druntime
          Assignee: nobody at puremagic.com
          Reporter: chalucha at gmail.com

Reduced test case:

```D
import core.stdc.stdlib : malloc;
import core.lifetime : emplace;

struct Foo {
    size_t foo;
    ~this() { } // works with this line commented out
}

extern(C)
void main() {
    auto p = malloc(Foo.sizeof);
    Foo* pay = emplace!Foo(p[0..Foo.sizeof], 1);
}

```

dmd -betterC test.d
returns:

/home/tomas/dlang/dmd-2.096.0/linux/bin64/../../src/druntime/import/core/internal/lifetime.d(35):
Error: Cannot use try-catch statements with -betterC
/home/tomas/dlang/dmd-2.096.0/linux/bin64/../../src/druntime/import/core/internal/lifetime.d(57):
Error: template instance `core.internal.lifetime.emplaceRef!(Foo, Foo,
int).emplaceRef.S.__ctor!()` error instantiating
/home/tomas/dlang/dmd-2.096.0/linux/bin64/../../src/druntime/import/core/lifetime.d(299):
       instantiated from here: `emplaceRef!(Foo, Foo, int)`
test.d(13):        instantiated from here: `emplace!(Foo, int)`


This worked with previous compilers.

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