Is hegemonic masculinity and hegemonic heterosexuality the same?

No. The ancient Greeks and Mediterranean cultures showing their influence, usually via the Romans, amply illustrate cultures that display hegemonic masculinity without hegemonic heterosexuality (to use these atrocious phrases as per your question).

Hegemony is a Marxist theory, referring to the social construct through which one social class dominates the others. The values, language, etc of the ruling class come to be seen as normal and "correct." One example of this would be AAVE ("ebonics")-- linguistically, it is actually a perfectly valid language, with consistency and its own grammatical rules, but it is perceived as "just slang" and improper. Gramsci, the theorist who created the idea of cultural hegemony, might say that society's rejection of ebonics stems from it being spoken predominantly by poor black people with less education; people in those categories don't fit into the dominant group.

Hegemony isn't formed by the ruling class actively oppressing... it's not about legally dictating certain things. It is, in fact, something of a compromise between the subordinate classes (the subaltern) and the ruling class. The idea goes that the ruling class controls the media, which dictates the ideas of what is right and wrong, and the subaltern absorbs them and internalizes them... then starts to perpetuate these ideas itself.

Hegemonic masculinity and hegemonic heterosexuality would thus both follow the model of cultural hegemony, so in that sense, they are the same. However, they are different in terms of the values they promote. [Straight] women are essential to hegemonic heterosexuality. They are not to hegemonic masculinity, for obvious reasons*.